Items

Specification

Appearance:

White or off-white crystalline powder

Clarity of solution:

Identification

UV

Infrared absorption

NMR absorption

Similar to working standards

Similar to working standards

Similar to working standards

Assay:

98.5-101.5%

Residue on ignition:

Not more than 0.20%

Heavy metals:

Not more than 10ppm

Loss on drying:

Not more than 0.5%

pH value(in 1% solution):

3.5-4.5

Chloride:

Not more than 0.1%

Sulfate:

Not more than 0.2%

Hydrogen sulfide and sulfur dioxide:

Negative

3-aminosalicylic acid:

Not more than 0.2%

Aniline:

Not more than 5µg/g

Phenol:

Not more than 5µg/g

4-aminophenol:

Not more than 200µg/g

2-aminophenol:

Not more than 200µg/g

Total impurities:

Not more than 1%

Other single impurity:

Not more than 0.2%